This invention relates to digital-type data communication systems. More particularly, the present invention relates to a computer-based data acquisition and control communications system operating as part of a television signal distribution network over bi-directional coaxial cable.
A number of cable television systems have been developed for two-way communication over coaxial cable to transmit data signals and television signals between subscriber locations and a central station. Such systems have been utilized for the control and monitoring of security systems in homes or businesses. Bi-directional cable communication systems have also proven useful in providing pay television services by monitoring the usage of the television by the subscriber and transmitting billing signals to a data processor located at a central station. Examples of such systems are disclosed in U.S. Pat. No. 3,794,922 issued to Osborn et al and U.S. Pat. No. 3,803,491 issued to Osborn.
Cable communication systems have been used in the past primarily for security monitoring and control functions and for controlling monthly subscription pay television. Recent developments in communications components and computer systems are making many additional applications technically feasible which will enable a subscriber to have a wide range of data acquisition and control uses. These applications include per-view premium television which allows the user to select and watch premium programs such as first-run movies on a pay-per-program basis, and user access to extensive data bases such as libraries and newspapers for the selective retrieval of large amounts of data to be viewed on the television screen. In addition, many electronic games can be provided from a central data base for home entertainment.
Moreover, sophisticated monitoring systems are contemplated which will have the capability of receiving and monitoring data from the user. These systems include remote meter reading techniques interfacing with home and business utilities to develop composite and simple billing for the customer, and energy management systems to assist the customer and the power company in more efficiently utilizing power consumption and conserving energy. Other types of monitoring systems which are becoming feasible include opinion polling, advertising feedback, home shopping and other user-service vender interfaces. In addition, a number of business applications are contemplated such as point-to-point data transmission, remote control operations and traffic control communications.
With the increased usage of such cable communication systems and the increased development of varied applications for such systems, the need has developed for more sophisticated and efficient data acquisition and control techniques. Most cable communication systems use some type of time multiplexing procedure in transmitting data which allows a central station to cyclically sample data from each of a number of home terminals over a fairly short period of time. This concept, called "time sharing or time division multiplexing (TDM)", is widely used in the computer and communications industries.